IMPROVEMENT OF HETEROLOGOUS PROTEIN PRODUCTIVITY USING RECOMBINANT YARROWIA-LIPOLYTICA AND CYCLIC FED-BATCH PROCESS STRATEGY

A cyclic fed-batch bioprocess is designed and a significant improvemen t of rice alpha-amylase productivity of recombinant Yarrowia lipolytic a is illustrated. A bioprocess control strategy developed and reported here entails use of a genetically stable recombinant cloned for heter ologous protein, use of optimized media for cell growth and enzyme pro duction phases, and process control strategy enabling high cell-densit y culture and high alpha-amylase productivity. This process control ca n be achieved through maintaining a constant optimal specific cell gro wth rate at a predetermined value (i.e., 0.1 h(-1)), controlling mediu m feed rate commensurate with the cell growth rate, and maintaining a high cell-density culture (i.e., 60-70 g/L) for high productivity of c loned heterologous protein. The volumetric enzyme productivity (1,960 units/L.h) achieved from the cyclic fed-batch process was about 3-fold higher than that of the fed-batch culture process (630 units/L.h). (C ) 1998 John Wiley & Sons, Inc.